Hexion Specialty Chemicals, Inc. signed a definitive agreement to purchase the global wax compounds business of Rohm and Haas Company. Terms of the agreement were not disclosed.  Closing is subject to governmental approvals.   Under the agreement, Hexion will purchase Rohm and Haas Company’s wax compounds technology and product lines, manufacturing equipment and other business assets.  The products include wax compounds for sheetfed and heatset printing processes, as well as solvent-based comp...